1. Field of the Invention
This invention relates to a cassette loading mechanism for a recording/reproducing device for loading a cassette enclosing a magnetic tape to a recording position. This invention also is utilized in the cassette loading mechanism in which several types of cassettes having different sizes can be selectively attached in the device for recording and/or reproduction.
2. Description of the Background Art
There are known several types of cassettes of different sizes for enclosing a magnetic tape as the magnetic recording medium. For recording/reproducing cassettes of different sizes, magnetic recording/reproducing devices, such as video tape recorders (VTRs), designed for the different sizes of cassettes, are employed. When recording/reproducing small-size cassettes using VTRs for large size cassettes, a cassette adapter is employed for loading the small-size cassette at the position of recording/reproducing the large-size cassettes.
There are disclosed different techniques utilized in the magnetic recording/reproducing device into which plural kinds of cassettes of different sizes can be loaded. For example, the Japanese Patent Laying Open No. 63731/1979 discloses a cassette type magnetic recording/reproducing device having a common opening for inserting a magnetic head and pinch roll and in which at least two kinds of large and small size tape cassettes can be attached into the same cassette loading section, wherein the recording/reproducing device includes a mechanism for driving a driving source of a small size cassette by the power transmitted from a driving shaft for a large size cassette. The Japanese Patent Laying Open No. 128048/1983 discloses a magnetic recording/reproducing device in which a unit for extracting the tape from the large size cassette and a unit for extracting the tape from the small size cassette may be used at least partially in common with each other. The Japanese Patent Laying Open No. 193502/1984 discloses a cassette loading mechanism in which a cassette adapter is used for the case in which the small size cassette is recorded and/or reproduced using a VTR for a large size cassette. In this cassette loading mechanism, the small size cassette may be introduced or taken out via a small size cassette insertion opening different from the cassette adapter insertion opening, while the cassette adapter is positioned at the cassette adapter insertion opening. The Japanese Patent Laying Open No. 227061/1984 discloses such a cassette loading mechanism which is provided with control means for controlling a cassette adapter so that the cassette adapter operation is discontinued upon insertion of the cassette adapter when it is detected whether the unit that has been introduced or taken out is the cassette adapter or the large size cassette. The Japanese Patent Laying Open No. 227062/1984 discloses an arrangement which is provided not only with the above control means but also with separate control means whereby the cassette adapter is halted at a predetermined position when the small size cassette is not inserted into the cassette adapter, when it is detected whether the cassette adapter and the small size cassette are present or not. The Japanese Patent Laying Open No. 1643/1985 discloses a cassette loading mechanism in which, when the cassette adapter is employed, the tape loading operation and the tape unloading operation may be carried out automatically by an electric motor. The Japanese Utility Model Laying Open No. 9037/1985 discloses a cassette loading mechanism in which a large size cassette and a small size cassette may be selectively loaded using an adapter for small size cassettes, and in which the adapter for the small size cassette may be retained in the device as it is emptied of the small size cassette.
In the Japanese Patent Application No. 198415/1987 filed in Japan on Aug. 7, 1987 and in the corresponding U.S. Pat. application Ser. No. 171746, now U.S. Pat. No. 4,866,550, filed in the United States under claiming the convention rights based on this Japanese Patent Application, the present inventor et al. have invented and disclosed a cassette loading mechanism making it possible to selectively attach a plurality of kinds of cassettes of different sizes for recording and/or reproduction. This cassette loading mechanism is designed for selectively attaching a large size cassette or a small size cassette for recording and/or reproduction without employing the cassette adapter. The cassette control unit provided with such a cassette loading mechanism is shown diagrammatically in FIG. 1. Referring to this figure, when a large size cassette 3 is introduced in a direction shown by the arrow mark 45 from a front cabinet 35, the cassette is loaded into the loading position for recording and/or reproduction, as it is held by a slider in the direction shown by the arrow mark 47. For loading a small size cassette, the cassette is introduced from an upper cabinet 24 in the direction shown by the arrow mark 49, and lowered in the direction shown by the arrow mark 51, so as to be attached in position in within an adapter chassis 14. Then, after a magnetic tape 1a is extracted by an adapter motor, not shown, in the direction shown by the arrow mark 53, the adapter chassis 14 is lowered in the direction shown by the arrow mark 55 for loading the small size cassette 1 in the predetermined recording/reproducing position.
When the adapter chassis 14 having the small size cassette 1 attached thereto is lowered, the adapter chassis 14 may be contacted with the large size cassette or a hand occasionally introduced into the cabinet, thus causing damage to the device.
On the other hand, a slider for holding and securing the large size cassette 3 is positioned in the downward path of travel of the adapter chassis 14. Therefore, when loading the small size cassette 1, it is necessary to shift the slider along the direction shown by the arrow mark 47 while the large size cassette 3 is not introduced into the cabinet. In the course of the movement of the slider, when the large size cassette 3, foreign matter or hand is introduced from the front cabinet 35, there is the risk that various component parts of the mechanism of the magnetic recording/reproducing device may be damaged. This presents a problem in that the operational safety in the cassette loading and removal operation is impaired.
The problem of the impaired operational safety is also presented in a cassette control unit dedicated to large or small size cassettes. That is, the component parts of the mechanism of the magnetic recording and/or reproducing device may be impaired by the foreign matter, hand or finger inserted via the cassette inserting opening after the large size cassette or the small size cassette is introduced via the predetermined cassette inserting opening so as to be loaded to the predetermined magnetic recording/reproducing position. For example, when the small size cassette is inserted by mistake via the large cassette inserting opening, there is the risk that other mechanisms or cassettes in the magnetic recording and/or reproducing device may be damaged.